Crystallization, microstructure development and dielectric behaviour of glass ceramics in the system [SrO · TiO2]-[2SiO2 · B2O3]-La2O3

Abstract

Various glasses in the system (65 - x)[SrO · TiO2]-(35)[2SiO2 · B2O3]-(x)La2O3, where x = 1,5,10 (wt%) were prepared by melting in alumina crucible (1375-1575 K). Heat treatment schedules were selected from DTA plots of respective glasses. X-ray diffraction studies of glass ceramic samples containing different concentrations of La2O3 revealed the formation of Sr2B2O5, Sr3Ti2O7 and TiO2 (rutile) phases. The addition of La2O3 results in the development of well formed, elongated crystallites of different phases. Results of the dielectric behaviour demonstrate higher values of dielectric constant for some of the glass ceramic samples. This can be ascribed to the relaxation polarization at the crystal-glass interface due to conductivity differences between crystalline and glassy phases. © 2002 Kluwer Academic Publishers.